Has anyone had success installing #3 330 heads on a 403? I would like to do up a set as they have 60cc chambers rather than the 83cc. I have studied the olds faqs with all the specs and the different cam angles,headbolt sizes and it looks like it shouldn't be any reason they couldn't be capable of working.The 403 is stock shortblock with a 224*.496 int.234*.520 ext. 112*lsa. I have a performer RPM intake for it and headers,the faqs chart shows between 9:1 to 10:1 comp. Any input on this subject would be helpful!!!!!!!!!
403 question
- Thread starter 87oldssalon302sbc
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87oldssalon302sbc said:
Assuming you drill out the bolt holes to 1/2", the 330 heads will bolt to the 403. You need to watch out for the pushrod holes, however. The 330 motors could have come with either a 45 degree or a 39 degree lifter bank angle. The pushrod holes will be different, depending on the angle. All 68-90 Olds motors (403 included) use the 39 deg bank angle.
Assuming you use the 330 heads, at a minimum you should install the 2.070/1.625 valves used on the big block Olds. Personally, I'd use big block heads on a 403 (they work on the 400 big block Olds motor) and select different pistons to raise the compression. BBO heads have 80 cc chambers.
I was at least gonna give them a good valve job,open the bowls a little and clean up the ports a little.The car is a 87'Olds cutlass with 3:23 posi.in the rear and a turbo 350 trans with 2500 stall.Its not gonna be a race car its just a toy.I have a choice of the 307 5a,the 403 4b,or the 330 #3s.Yes I will be drilling out the bolt holes and the push rod holes,I think you also have to drill the dowel holes bigger.I already had the engine running with the stock heads and complete overhaul,new pistons polished crank new bearings,the hole nine yards.I was wondering if the 330 heads would make it a little more fun.
I ran into the pushrod problem.. talk about a major bummer!! the pushrod holes need to be reamed out and chamfered!!! the head bolt holes need to be drilled to 1/2 as well.. I ported mine.. just because.. i wanted to and they really really woke up my 403!!
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